Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove connector 100 from the PCB
Disconnect the fan power connector from the fan assembly

Measurement:

Measure the resistance between the brown, blue and earth pins on
connector 100 to the corresponding pins on the fan power connector.
Expect continuity / zero resistance on each test.
Also visually inspect the condition of the harness.